From: "Tian, Kevin" <kevin.tian@intel.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Wei Liu" <wl@xen.org>, "Nakajima, Jun" <jun.nakajima@intel.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH 1/3] Revert "x86/vvmx: fix virtual interrupt injection when Ack on exit control is used"
Date: Tue, 24 Mar 2020 08:49:27 +0000 [thread overview]
Message-ID: <AADFC41AFE54684AB9EE6CBC0274A5D19D7E5D72@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <3d0286dd-1702-e7dd-a0a1-795cbd54ccb3@suse.com>
> From: Jan Beulich <jbeulich@suse.com>
> Sent: Tuesday, March 24, 2020 4:10 PM
>
> On 24.03.2020 06:41, Tian, Kevin wrote:
> >> From: Roger Pau Monné <roger.pau@citrix.com>
> >> Sent: Monday, March 23, 2020 10:49 PM
> >>
> >> On Mon, Mar 23, 2020 at 09:09:59AM +0100, Jan Beulich wrote:
> >>> On 20.03.2020 20:07, Roger Pau Monne wrote:
> >>>> This reverts commit f96e1469ad06b61796c60193daaeb9f8a96d7458.
> >>>>
> >>>> The commit is wrong, as the whole point of nvmx_update_apicv is to
> >>>> update the guest interrupt status field when the Ack on exit VMEXIT
> >>>> control feature is enabled.
> >>>>
> >>>> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> >>>
> >>> Before anyone gets to look at the other two patches, should this
> >>> be thrown in right away?
> >>
> >> I would like if possible get a confirmation from Kevin (or anyone
> >> else) that my understanding is correct. I find the nested code very
> >> confusing, and I've already made a mistake while trying to fix it.
> >> That being said, this was spotted by osstest as introducing a
> >> regression, so I guess it's safe to just toss it in now.
> >>
> >> FWIW patch 2/3 attempts to provide a description of my understanding
> >> of how nvmx_update_apicv works.
> >>
> >
> > I feel it is not good to take this patch alone, as it was introduced to fix
> > another problem. W/o understanding whether the whole series can
> > fix both old and new problems, we may risk putting nested interrupt
> > logic in an even worse state...
>
> Well, okay, I'll wait then, but it would seem to me that reverting
> wouldn't put us in a worse state than we were in before that change
> was put in.
Roger needs to make the call, i.e. which problem is more severe, old or
new one.
Thanks
Kevin
next prev parent reply other threads:[~2020-03-24 8:49 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-20 19:07 [Xen-devel] [PATCH 0/3] x86/nvmx: attempt to fix interrupt injection Roger Pau Monne
2020-03-20 19:07 ` [Xen-devel] [PATCH 1/3] Revert "x86/vvmx: fix virtual interrupt injection when Ack on exit control is used" Roger Pau Monne
2020-03-23 8:09 ` Jan Beulich
2020-03-23 14:48 ` Roger Pau Monné
2020-03-24 5:41 ` Tian, Kevin
2020-03-24 8:10 ` Jan Beulich
2020-03-24 8:49 ` Tian, Kevin [this message]
2020-03-24 10:47 ` Roger Pau Monné
2020-03-24 11:00 ` Tian, Kevin
2020-03-20 19:07 ` [Xen-devel] [PATCH 2/3] x86/nvmx: clarify and fix usage of nvmx_update_apicv Roger Pau Monne
2020-03-24 6:03 ` Tian, Kevin
2020-03-24 9:50 ` Roger Pau Monné
2020-03-24 10:11 ` Tian, Kevin
2020-03-24 11:22 ` Roger Pau Monné
2020-03-24 11:33 ` Tian, Kevin
2020-03-24 12:18 ` Roger Pau Monné
2020-03-26 5:49 ` Tian, Kevin
2020-03-20 19:07 ` [Xen-devel] [PATCH 3/3] x86/nvmx: update exit bitmap on vmexit Roger Pau Monne
2020-03-24 6:22 ` Tian, Kevin
2020-03-24 9:59 ` Roger Pau Monné
2020-03-24 10:16 ` Tian, Kevin
2020-03-24 11:24 ` Roger Pau Monné
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